i) Field of the Invention PA1 ii) Description of the Related Arts
The present invention relates to a numerically controlled lathe capable of successively carrying out usual machining and balance correction machining.
Conventionally, in order to take a dynamic balance of a workpiece, as shown by a flow chart in FIG. 16, at a final step after finishing the usual machining of a workpiece using a lathe or the like, balance correction machining of the workpiece is carried out. FIG. 17 schematically shows balance correction machining of a workpiece W. First, a workpiece W is mounted on a balancing machine and is rotated at a predetermined rotation speed by a drive motor 101 via a universal coupling 102, and an amount of imbalance and phase of the workpiece W is measured using signals output from a vibration sensor 103 and a rotation angle detector 104 in an imbalance measuring circuit 105, and a biased weight part of the workpiece W is cut off by a drilling machine or the like attached to or separated from the balancing machine so as to carry out balance correction machining. Further, the balance test (balance measuring) of the workpiece W is performed again and, when the workpiece W has not pass the balance test yet, the balance correction machining is executed again.
In the conventional balance correction method, as described above, the workpiece W is removed from the machining apparatus and is then mounted to the balancing machine for carrying out the balance correction. Hence, it is a waste of labor and time and deleats the object of automation.